Field of the Invention
The present invention is directed generally to scheduled fluid control valves and, more specifically, to fluid control valves which perform a pre-established schedule in response to pressure variations in the controlled fluid.
Pressurized fluid distribution systems are used throughout a large variety of industries, from oil pipelines to lawn watering systems. Remote valves are often required to control such systems and are generally operated by electrical or pneumatic signals received from a central location. These control systems require an electrical or pneumatic motor or solenoid valve actuator at each remote valve and electrical control wires or control pipes connecting the motors to the central control location. As a result, the additional equipment and installation adds significantly to the cost of the distribution system, making the controlled system commercially impractical in certain applications.
There is a need in the art for an inexpensive, reliable valve which does not require additional equipment, pipes, or wiring to perform a control schedule. A number of valves attempt to address this problem using variations or pulses in a controlled fluid. For example, U.S. Pat. Nos. 2,793,908 (Carver, 1957) and 3,459,208 (Clyde, 1969) disclose fluid actuated valves utilizing drums containing continuous series of notches whereby fluid flow through the devices is controlled. As a result of internal construction, both of these valves are dependent upon vertical orientation. Additionally, U.S. Pat. No. 4,196,654 (Stearns, 1980) teaches a valve motor which may be used to reciprocally rotate a valve ninety degrees (90.degree.) in response to certain minimum variations in the pressure of a separate controlling fluid. The Stearns device, however, is not operable as a controlled valve itself because it requires a controlled fluid system in addition to the system in which the valve would be inserted. Further, the known valves do not allow for adjustments in the flow of the fluid through the valve as a variable to be added to the schedule performed by the valve.
The present invention is a simple, reliable and inexpensive valve that performs a pre-established schedule operated by pressure pulses in the controlled fluid itself. The valve responds to changes in the pressure of the controlled fluid by performing a pre-established cycle having a pattern of steps which are selectively initiated by the fluid pressure pulses. Use of the valves in a distribution system, allows the system to be divided into a number of coordinated portions each performing its assigned schedule.
The valves may be added to a pre-existing, installed system without the use of additional control equipment. Further, the valve may be manually adjusted to provide a plurality of flow rates and timing schedules to accommodate a wide variety of conditions.
It is therefore an object of the present invention to provide an improved scheduled fluid control valve that employs pressure pulses in the controlled fluid to perform a pre-established schedule.
It is another object of the present invention to provide a scheduled fluid control valve that may be installed in pre-existing fluid distribution systems without additional control equipment.
It is a further object of the present invention to provide an improved scheduled fluid control valve that may be easily altered to perform a variety of schedules.
It is another object of the present invention to provide an improved scheduled fluid control valve that may also be used to limit the flow rate of fluid through the valve according to a pre-established schedule.
It is a further object of the present invention to provide an improved scheduled fluid control valve that is adaptable to a wide range of distribution system pressures by appropriate adjustment, fabrication materials, and tolerances.